Detection and Molecular Characterization of Escherichia coli from Wastewater Environments in Two University Campuses in Nigeria.

Abstract

Background: Escherichia coli (E. coli) is the most prominent bacterial pathogen that causes urinary tract infections (UTIs), and the rate of resistance to most used antibiotics is alarmingly increasing.

Methods: This study assessed the hostel gutters of two Nigerian universities, the University of Nigeria, Nsukka (UNN) and Kogi State University, Anyigba (KSU), for E. coli and its antimicrobial resistance genes (ARGs). Oxoid Chromogenic UTI agar was used to isolate uropathogenic E. coli (UPEC), identified using standard biochemical tests. The virulence and resistance genes of the isolates were further characterized using molecular techniques.

Results: A total of 906 UPEC were isolated in this study, of which 63 isolates were selected for antimicrobial susceptibility tests. The UPEC isolates showed 100% resistance to amoxicillin/clavulanic acid, vancomycin, and penicillin G, while a complete sensitivity of the isolates to meropenem and ciprofloxacin was observed. The index of isolates showing multidrug resistance ranged from 0.33 to 0.73. The level of multiple drug resistance (MDR) exhibited by the UPEC isolates from effluent was significantly higher compared to those from influent (p < 0.05). The ARGs detected were blaOXA-1 8 (38.1%), blaCTX-M3 8 (38.1%), and ant(2)-la 20 (95.2%). Virulence genes encodings beta-glucuronidase (uidA) and hemolysin A (hlyA) were detected in 95.2% of UPEC isolates.

Conclusion: The current study showed that UPEC is widely distributed in the environment of two Nigerian universities. The index range of MDR and the circulation of ARGs and virulence genes in the environment suggest a potential health concern, thus warranting further investigation.